Patent GB-1322513-A (GB)
Title: Apparatus for joining sheet materials
IPC: B29C65/18
Filed: 1970-09-10
Abstract: 1322513 Seaming non-metallic sheet material BIEDERMANN GmbH Gebr 10 Sept 1970 [11 Sept 1969] 43372/70 Heading B5K Sheets 17, 18 of material, e.g. leather, are joined to each other along two edges forming an overlap area 43 of given width by inserting a joining strip 29 having heat activatable surfaces between the overlapping edges and applying heat and pressure to the overlapping area to activate the surfaces of the strip 29 to make it adhere to both overlapping edges. A stop 2 is urged by springs 4 outwardly of a groove 1<SP>1</SP> in a sheet supporting surface 1. A heating and pressing member 5 is mounted so as to be vertically movable above the surface 1 and has a head 12 sliding in a dovetail groove 10 in a slide 7 which has a head 11 sliding in a dovetail groove 9 of a slide 6 connected for vertical movement to a drive rod 8 on a frame 5<SP>1</SP>. The slides 6, 7 permit horizontal adjustment of the member 5. Set screws 13, 14 are provided. A heat insulating and heat resisting lining 15, e.g. of thermally stable glass, is attached to the member 5. The member 5 may be heated by elements 50 or may be a high frequency dielectric heating electrode. A hold-down member 16 may be made of thermally stable glass and is mounted, similarly to the member 5, by two slides 19, 20 on a drive rod 21 on the frame 5<SP>1</SP>. The joining strip 29 comprises a strip or ribbon having a thermoplastic layer on each side and has a protective strip or ribbon 29<SP>1</SP> covering one of these layers. As the strip 29 is fed from a supply roller 28, the strip 29<SP>1</SP> is stripped therefrom by a roller 28<SP>1</SP>. A guide roller 30<SP>1</SP> leads the strip 29 into a channel 30 from which it passes between motor-driven pull-off rollers 31, 31<SP>1</SP>. The strip 29 is cut simultaneously with application of heat and pressure by a blade 33 on the member 5 co-operating with a stationary blade 34. Stroke limiting means, Fib. 3, to ensure that a small gap is always left between the member 5 and the surface 1, comprises a lever 35 privoted at 36<SP>1</SP> and one arm of which has an adjustment screw 38 threaded therethrough to bear against a stop surface 37. The other arm of the lever 35 has forked members 40 which receive the rod 8 therebetween. The downstroke 42 of the rod 8 is limited by the engagement of a flange 41 on the rod 8 with the lever 35. At the start of the operation, the members 5, 16 are elevated and the slides 6, 7, 19, 20 are adjusted to select the width of the overlap area preferably to correspond to the width of the strip 29. One sheet 17 is placed on the surface 1 and is positioned against the stop 2. The member 16 is lowered to press the sheet 17 against the surface 1. A timing relay actuates the rollers 31, 311 and the desired length of strip 29 is fed on to the edge of the sheet 17. The sheet 18 is positioned above the stop 2 so that its edge is aligned against the side surface 16<SP>1</SP> of the member 16. If necessary, the desired length of the downstroke 42 may be adjusted by the screw 38. The member 5 is lowered and pressed towards the surface 1 to depress the stop 2 against the springs 4. Simultaneously, the strip 29 is severed and, after joining, the members 5, 16 are raised.